Apparatus for digging trenches

ABSTRACT

An apparatus for digging a trench including (a) a substantial vertical guide means ( 2 ); (b) mounting means ( 4 ) connected to the guide means ( 2 ) and movable substantially parallel to the guide means ( 2 ); (c) first drive means to move the mounting means ( 4 ) relative to the guide means ( 2 ); (d) a chain digger attachment ( 1 ) including an elongated frame ( 5 ) and a continuous digging chain ( 6 ) substantially surrounding the periphery of the frame ( 5 ), the attachment ( 1 ) being pivotally connected at or adjacent one of its ends to the mounting means ( 4 ); (e) second drive means ( 15 ) to rotate the continuous digging chain ( 6 ) about the frame ( 5 ); and (f) third drive means ( 24 ) to pivot the attachment ( 1 ) about the mounting means ( 4 ).

FIELD OF THE INVENTION

[0001] The invention relates to an apparatus for digging trenches. Inparticular, the invention relates to a chain digging assembly forattachment to a carrier and a method of forming trenches using such achain digging assembly.

BACKGROUND OF THE INVENTION

[0002] Trenches are required to be dug in a number of industries. In thebuilding industry, for example, trenches are required to be dug for thepurpose of laying foundations.

[0003] In another example, the close proximity of trees to buildings,fences, pathways and other structures have given rise to problems. Theroots of such trees may cause damage by interfering with the foundationsof the structures, lifting the pathways surrounding the structures or bycausing soil-moisture movement problems.

[0004] In many instances, it becomes necessary to cut the roots of thetree causing the damage. Basically, a trench is dug in close proximityto the tree. The roots are cut in order to render them inactive and stopthem from encroaching further.

[0005] In the past, typical trenching apparatus have been a backhoe or atractor type vehicle which has a digging bucket attached to a boom.These machines make wide transverse trenches into the ground and areused to prepare trenches for house foundations and pathways. However,once the operating environment is confined, these machines are difficultto manoeuvre and unable to cut tree roots and the ground cleanly.

[0006] One alternate type of machine has been specifically designed tooperate in a confined environment where narrow trenches are required andlarge root diameters need to be cut. This machine includes a circular ordisc like digger attachment mounted at one end of a small tractor typevehicle. The disc has a number of teeth, each with a cutting edge,located about the periphery of the disc. As the disc is rotated theteeth rotate and by lowering the disc the teeth dig into the ground. Thedisc does not remove the spoil from the trench and separate removal ofthe spoil is necessary. The disc is of about 1.2 meters in diameter andcan cut a trench down to about 0.6 meters in depth.

[0007] However, this purpose built machine is still not able to carryout all the desired functions in a confined environment. For example asthis machine uses a disc, it is not able to cut around and under anyservices which may be present such as water pipes, power lines or gaspipes.

[0008] This machine is also not able to cut deep trenches as the discdiameter is limited. Consequently this machine was modified to alsoinclude an elongated digger which has an appearance similar to a chainsaw. The elongated digger is pivotally attached to the side of thevehicle and is used to bring spoil out of the trench initially cut bythe disc and when deeper trenches are required. In operation, theelongated digger is rotated until it engages the ground. In the almostvertical position the digger can form a trench of about 1 meter indepth. However, to avoid fouling services which may be present it isnecessary to employ a complicated combination of vehicle front and backmovement with the pivotal movement. This is time consuming and may bedangerous as the services may be accidentally fouled.

[0009] A further digger machine is disclosed in Australian Patent No.620,271 (“Wallace”). This patent discloses a chain digger of the chainsaw type pivotally attached to a boom which is in turn pivotallyattached to a vehicle. In essence, the apparatus disclosed in Wallaceuses a combination of two pivotal movements. In operation, the chaindigger is positioned in a non-vertical trenching position for engagingthe ground. The deeper the desired trench the more the relativerotational movement between the boom and the chain digger. If a verticalhole is required, the operator must simultaneously and continuallyadjust the orientation of the boom and the chain digger. The chaindigger also includes a pusher foot which can push the vehicle forward asthe trench progresses in steps.

[0010] Like the other prior devices the difficulty in manoeuvring thechain digger makes the precise movement of the chain digger difficult tocontrol and may be dangerous in confined environments where liveservices are present.

[0011] Object of the Invention

[0012] The present invention therefore aims to provide an improvedapparatus for cutting and digging trenches which has sufficientversatility to enable cleanly cut trenches to be prepared in confinedenvironments.

SUMMARY OF THE INVENTION

[0013] According to the present invention there is provided an apparatusfor digging a trench including:

[0014] (a) a substantial vertical guide means;

[0015] (b) mounting means connected to the guide means and movablesubstantially parallel to the guide means;

[0016] (c) first drive means to move the mounting means relative to theguide means;

[0017] (d) a chain digger attachment including an elongated frame and acontinuous digging chain substantially surrounding the periphery of theframe, the attachment being pivotally connected at or adjacent one ofits ends to the mounting means;

[0018] (e) second drive means to rotate the continuous digging chainabout the frame; and

[0019] (f) third drive means to pivot the attachment about the mountingmeans.

[0020] In this way, a wide variety of trenching positions are possibleby using the combination of pivotal movement of the chain diggerattachment and vertical movement of the mounting means. This arrangementrepresents a substantial improvement over the prior art and makes itpossible to cut trenches in different positions relative to, forexample, the vehicle upon which the apparatus is mounted and further inplaces where movement is confined or live services are in the vicinityof the trench. Preferably, the third drive means can pivot theattachment through up to 180 degrees.

[0021] Typically, the guide means comprises a frame along which themounting means may slide to allow movement into the various trenchingpositions.

[0022] In a preferred form of the invention, the guide means istelescopic. Typically, in this form of the invention, the guide meansincludes sections in the frame that slide into one another. If the guidemeans is not telescopic, the height of the guide means remains fixed anddoes allow for the fact that the apparatus may need to be used insurroundings where there are height restrictions. In the telescopedform, the overall height of the apparatus can be lowered by the varioussections of the guide means sliding within each adjacent section. Inthis form of the invention, the overall height of the apparatus is stilldependant on the length and angle of the chain digger attachment.

[0023] In another preferred form, the apparatus further includes fourthdrive means to move the mounting means transversely of the guide means.

[0024] The transverse movement of the mounting means adds yet a furtherdimension to the ability of the apparatus to dig a trench. Thetransverse movement allows the apparatus to dig a trench according tothe location of services and built structures without moving thelocation of the base machine. Typically, the transverse movement may bea combination of a pair of independent transverse movements. In thisarrangement, a further drive means is interposed between the fourthdrive means and the mounting means. The fourth drive means moves thefurther drive means, and the further drive means moves the mountingmeans. This permits a wider range of transverse movement of the mountingmeans, beyond the width of the base machine.

[0025] Preferably, the mounting means is a platform. The use of aplatform is advantageous as it provides a convenient base on which tomount the second drive means which sits on the platform as it is movedup and down the guide means, which may be in the form of a frame. Inthis form of the invention, preferably, the platform includes bracketswhich engage around slots in the frame to support the platform at anydesignated height.

[0026] In a particularly preferred form, the chain digger attachment iscapable of being pivoted into an indefinite number of trenchingpositions. In one preferred form of the invention, the chain diggerattachment is capable of being pivoted into a position that issubstantially vertical to the guide means. In this position, theattachment can function substantially as an auger.

[0027] The digger chain more preferably, includes a plurality of cuttingscoops which may be evenly spaced around the periphery of theattachment. The leading edges of the scoops are sharpened for cuttinginto the earth and in this way make for the easy removal of earth orother material to be removed.

[0028] In yet a further preferred form of the invention, the first,second, third, fourth and/or fifth drive means are hydraulically driven.

[0029] The digging apparatus of the invention by combining at leastvertical and rotational movement permits the apparatus to be operated invery confined environments without the need for synchronous movement ofthe vehicle to which the apparatus is connected. By a combination ofmovements, the invention allows trenches to be prepared in circumstancesthat were hitherto unable to be prepared using prior art apparatus. Forexample, trenches can now be prepared with ease where services arepresent in the ground across the pathway of a proposed trench. The chaindigger attachment can be angled to prepare the trench up to the serviceand then adjusted to be substantially vertical with the ground and thespoil removed by the chain digger attachment being operated as an auger.In certain situations, once the trench has been prepared next to theservice, the digger attachment may even be positioned to trenchunderneath the service.

DESCRIPTION OF THE DRAWINGS

[0030] The invention will now be further illustrated by reference to theaccompanying drawings.

[0031]FIG. 1 is a side view of the apparatus for digging trenches whichis the subject of the invention.

[0032]FIG. 2 is a partial side view of the chain digger attachment ofFIG. 1 shown in various digging positions.

[0033]FIG. 3 is a partial end view of the chain digger attachment ofFIG. 1 shown in various trenching positions.

[0034]FIG. 4 is a reverse side view of the frame and chain diggerattachment of FIG. 2.

[0035] In the drawings, like numbers refer to the same features in eachof the Figures.

[0036]FIG. 1 shows in broad schematic form the trenching apparatus whichcomprises a chain digger attachment 1 connected through mountingplatform 4 to frame 2. Frame 2 is mounted upon vehicle 3. The specificdetails of each of the components is described below, however, in broadoperation chain digger attachment 1 is capable of being pivoted aboutthe mounting platform 4 into a number of trenching positions (as shownin FIG. 2). Typically, the chain digger attachment 1 is about 2.5 metersin length. Mounting platform 4 (and consequently chain digger attachment1) can move up and down frame 2.

[0037] This versatility is further shown in FIG. 2. In particular, thechain digger attachment 1 may achieve a trenching position parallel withframe 2 (shown as A-A in FIG. 2) and vertical to the ground. Inoperation, the chain digger attachment 1 can then function essentiallyas an auger by trenching a hole that is perpendicular with the ground.The digging of the trench is achieved by the mounting platform 4 beingmoved down into the ground.

[0038] As further shown in FIG. 2, the chain digger attachment 1 can bepivoted into an infinite number of different positions. Accordingly awide variety of trenching positions are possible by using thecombination of pivotal movement of the chain digger attachment 1 andvertical movement of the mounting platform 4. It is therefore possibleto cut trenches in different positions relative to vehicle 3 than iscurrently possible with known apparatus.

[0039] The specific details of the apparatus are further described withreference to FIGS. 2, 3 and 4.

[0040] Chain digger attachment 1 comprises a support frame 5 with guidewheels 7 over which is passed the digging chain 6. In operation, thedigging chain 6 moves around the support frame 5 in an ellipticalpathway. Guide wheels 7 are attached to each end of support frame 5 toguide the digging chain 6 around the two ends of the ellipse. Thedigging chain 6 has a plurality of cutting scoops 8 evenly spaced aroundits perimeter. The leading edge 9 of each of the cutting scoops 8 aresharpened for cutting the earth and/or tree roots and are designed toretain and transport the earth to the surface. The chain diggerattachment 1 has an aperture at the top end (not shown) to receive axle10 which when rotated drives digging chain 6.

[0041] Support right angle platform 4 is movably mounted to plate 21 bybrackets 11 which engage around slots in plate 21. The support rightangle platform 4 moves up and down the channels 13 with the brackets 11engaging in and around slots 12 to hold the support right angle platform4 in place at any designated height. As more clearly shown in FIG. 4,support right angle platform 4 has a horizontal surface 14 on whichmotor 15 is mounted. Motor 15 drives cog 16 which ultimately drives axle10 and in turn the digger chain 6.

[0042] A two sided mounting plate 17 is pivotally connected by journals18 to corresponding cross-bars 19 on each side of the support platform4. An aperture (not separately shown) in each mounting plate 17corresponds to the aperture in support frame 5 and receives axle 10which is driven by cog 22. Cog 22 is connected by chain 23 to cog 16(which as described above is driven by motor 15).

[0043] Mounting plate 17 holds the digger chain 6 in its varioustrenching positions as illustrated in FIG. 2 as W, X, Y and Z. Thosepositions may be infinitely varied by operation of piston 24 on mountingplate 17 via pin 25. Typically the positions may span up to 180 degrees.Piston 24 is hydraulically driven by movement of hydraulic fluid throughthe fluid inlet 26 and fluid outlet 27.

[0044] As shown in FIG. 3, digger chain 6 may be moved laterally withrespect to vehicle 3, or with regard to the positioning required oraccess available. In FIG. 3, three positions K, L, M are shown, thoughit is to be understood that an infinite number of variations arepossible.

[0045] In operation, the vehicle 3 is positioned and digger chain 6 isrotated about axle 10 to engage the ground. The digger chain 6 isalready moving under the influence of motor 15. The scoops 9 cut intothe earth and roots. The digger chain attachment 1 can be moved furtherinto the earth by vertical movement of it down frame 2. This is actuatedhydraulically in the same way as the pivotal motion of chain diggerattachment 1 about axle 10.

[0046] By combining vertical and pivotal movement it is possible to digtrenches deeper and in more confined areas than is currently possiblewith known machines. Likewise, it is possible to dig precisely aboutservices. The position of the trench can also be readily varied.

[0047] It is to be understood by those skilled in the technology thatmany variations or modifications in details of design or constructionmay be made without departing from the essence of the present invention.Such skilled addressees will appreciate that all such modifications andadaptations are included in the scope of the invention. Therefore, theinvention should be understood to include all such variations andmodifications within its scope.

The claims defining the invention are as follows:
 1. An apparatus fordigging a trench including: (a) a substantial vertical guide means; (b)mounting means connected to the guide means and movable substantiallyparallel to the guide means; (c) first drive means to move the mountingmeans relative to the guide means; (d) a chain digger attachmentincluding an elongated frame and a continuous digging chainsubstantially surrounding the periphery of the frame, the attachmentbeing pivotally connected at or adjacent one of its ends to the mountingmeans; (e) second drive means to rotate the continuous digging chainabout the frame; and (f) third drive means to pivot the attachment aboutthe mounting means.
 2. The apparatus according to claim 1 , wherein theguide means is a frame along which the mounting means slides.
 3. Theapparatus according to either claim 1 or claim 2 , wherein the guidemeans is telescoped.
 4. The apparatus according to claim 2 , wherein theframe includes at least two sections which slide within each other toallow telescopic extension and retraction.
 5. The apparatus of any oneof claims 1 to 4 wherein the third drive means is adapted to pivot theattachment about the mounting means through up to 180 degrees.
 6. Theapparatus according to any one of claims 1 to 5 , including fourth drivemeans to move the mounting means transversely of the guide means.
 7. Theapparatus of claim 6 including fifth drive means interposed between thefourth drive means and the mounting means to move the mounting meanstransversely of the guide means.
 8. The apparatus of any one of claims 1to 7 , wherein the mounting means is a platform.
 9. The apparatus ofclaim 8 , wherein: (a) the platform further includes brackets; and (b)the frame further includes slots, wherein in use the brackets engage inand around the slots to support the platform at a predetermined height.10. The apparatus of any one of claims 1 to 9 , wherein the chain diggerattachment is an auger.
 11. The apparatus of any one of claims 1 to 10 ,wherein the digger chain includes a plurality of cutting scoops.
 12. Theapparatus of claim 11 , wherein the digger chain includes a plurality ofcutting scoops evenly spaced around the periphery of the attachment. 13.The apparatus of claim 11 or claim 12 , wherein the leading edges of thescoops are sharpened.
 14. The apparatus of any one of claims 1 to 13wherein the first, second, third, fourth and/or fifth drive means arehydraulically driven.
 15. An apparatus for digging a trenchsubstantially as hereinbefore described with reference to theaccompanying drawings.